One of the things that makes space travel so expensive is the fact that rockets, for the most part, can't be reused. So everytime you launch something into orbit, you have to rebuild part of the vehicle. So it's been a long-term goal of many space organizations, both public and private, to build a fully reusable launch system. To date, however, the best anyone's been able to do is to only be able to reuse parts of a rocket.

Earlier this week, however, SpaceX took itself one step closer to its goal of a reusable rocket with a successful test of its "Grasshopper" rocket, which consists of the first stage of one of their Falcoln 9 rockets, but with a vertical takeoff and landing system. The rocket traveled 12 stories into the air, hovered for a little bit, then safely landed back down on the ground. The total flight lasted for 29 seconds.

(Also, to give people an idea of how big the Grasshopper is, SpaceX CEO tweeted this image, which shows a six-foot tall dummy of a cowboy on board the rocket.)

With the success of this test, SpaceX plans on continuing testing over the next few months, pushing it towards its goal of a successful orbital flight and landing.